Here's the series of events that happened after I got everything I needed to fight the lich:
-Acquire mods, two of which are not the same mod that was revealed post-mission. (Said Jahu, menu tells me Ris; Said Fass, menu tells me Netra)
-Apply mods on parazon in random order: Vome, Netra, Ris
-Attempt 1: Take on lich for the first time, get the animation when the first bar of HP is depleted, all three mod names are chanted in order
-Lich falls to his knees, game is soft locked after holding D to Vanquish and squad has to extract for me
-Attempt 2: Only the first two mods are chanted on the animation, lich disappears once it ends
-Attempt 3: Swap the last two mods, take on the lich, first mod is chanted, the second is marked red and the lich defeats me properly
-Attempts 4-6: I revert to the original mod order. I have to get to the end of the last bar for the animation to happen, and only two of the mods are chanted but I get either soft locke...